1. Field of the Invention
The invention relates to a press arrangement for treating a fibrous web, especially a paper or board web, having at least two press rolls to form at least one press nip. Moreover, it relates to a press roll.
2. Discussion of Background Information
In the shoe presses which have been customary utilized, the mating roll assigned to a respective shoe press roll on the operator""s side and on the drive side is respectively mounted by way of a swinging roller bearing, the two swinging roller bearings being installed as locating bearings. The floating bearing function is implemented outside the bearing housing and the actual force flow on the operator""s side by way of displaceable sliding bearings between the framing and the bearing housing. Inter alia, this entails the disadvantage that the relevant press module cannot be used sufficiently universally, which applies in particular to multi-roll presses. This is because the two opposite displaceable sliding bearings are always required at the sides on the bearing housing. Because of the unfavorable relationship between the distance between the guides and the length of the guides, there is the risk of tilting. This also applies to the usual conventional roll mountings having a displaceable bearing outer ring as a floating bearing, the displacement under pressing force being particularly critical here.
As a result of the aforementioned disadvantages, an uncontrolled axial bearing force may be produced, which shortens the service life of the roll mounting considerably and has a detrimental effect on the framing.
The object of the invention is to provide an improved press arrangement of the type mentioned at the beginning in which the abovementioned disadvantages are eliminated. In addition, the intention is to provide a press roll which is in particular suitable for such a press arrangement and can be used universally as a standard press module in the greatest possible number of press designs. The useful duration of the press roll bearings, in particular in the case of mating rolls on shoe presses, is to be increased and capable of being calculated. In particular, a virtually constant, preferably minimum axial force is also to be ensured. Such a press roll is also to be capable of being used, in particular, for so-called combipresses and multi-roll shoe presses.
With regard to the press arrangement, according to the invention this object is achieved by at least one press roll being mounted on at least one roll end by utilizing a floating bearing, whose bearing rings, arranged inside the bearing housing, can be displaced relative to each other in the direction of the roll axis. The two bearing rings of the floating bearing can preferably also be tilted relative to each other.
The relevant press roll can thus expand in any desired way without any sliding of a bearing outer ring or other guides under load being necessary to equalize the length. The relevant press roll can be used universally as a press module in an extremely wide range of press designs. The floating bearing function is fulfilled within the bearing housing. Thus, for example, the use for so-called combipresses can also readily be conceived of. An oblique installation position is possible without problems. New suspension points for the entire press module are also possible. Moreover, the respective bearing housings can be connected directly, permanently and compactly to the framing. The overall result is a more cost-effective construction.
In one embodiment the two bearing rings of the floating bearing can be tilted relative to each other, wherein the maximum angle of tilt can be about 0.5xc2x0, for example.
In a preferred practical embodiment of the press arrangement according to the invention, the two bearing rings are supported on all sides by bearing elements arranged between them. The bearing elements provided can, in particular, be bearing rollers.
A corresponding floating bearing is advantageously provided at least on the operator""s side.
After the floating bearing function has been implemented within the bearing housing, the relevant bearing housing can then be permanently connected to the framing.
The press arrangement can comprise at least one shoe press, in this case advantageously at least one mating roll assigned to a respective shoe press roll being mounted on at least one roll end by utilizing a floating bearing.
The press roll bearing can be connected to the bearing housing of press rolls by positive connecting elements which permit displacement arising from a change in length of the rolls. The result is thus, in particular, flexural elasticity in the cross-machine direction.
The press roll according to the invention is defined in that it is provided at least one roll end with a floating bearing, whose bearing rings, arranged inside the bearing housing, can be displaced relative to each other in the direction of the roll axis.
The invention provides for a press arrangement for treating a fibrous web comprising, at least two press rolls arranged to form at least one nip, at least one of the at least two press rolls comprising at least one end which is mounted to a bearing housing via floating bearing, wherein the floating bearing comprises bearing rings which can move relative to each other in an axial direction of the at least one press roll. The at least one press roll may be floatingly mounted to the housing via the floating bearing. The fibrous web may comprise one of a paper web and a board web. The bearing rings may be tiltable relative to each other. A maximum angle of tilt may be about 0.5xc2x0. The bearing rings may be separated by bearing elements which are arranged between them. The bearing elements may comprise bearing rollers. The floating bearing may be provided on at least an operator""s side of a press arrangement. The housing may be permanently connected to one of a framing and a swinging arm. The at least two press rolls may comprise at least one shoe press and at least one mating roll, the at least one mating roll is the at least one of the two press rolls having at least one end which is mounted to the bearing housing via the floating bearing. The press may further comprise at least one additional press roll arranged to form an additional press nip with one of the two press rolls, the at least two nips are formed by one of the press rolls, and wherein the one press roll is adjustably and moveably mounted via bearings to the bearing housing.
The invention also provides for a press roll for treating a fibrous web, comprising: a press roll rotatably mounted relative to a bearing housing via at least one floating bearing, wherein the floating bearing comprises bearing rings which can move relative to each other in an axial direction of the press roll. The bearing rings can tilt relative to each other. The tilt may be limited to a maximum angle of about 0.5xc2x0. The bearing rings may be separated by bearing elements which are arranged between them. The bearing elements may comprise bearing rollers.